Recent tree sap-collecting systems consist of a network of interconnected tubings allowing the sap collected from trees to be vacuum-sucked directly to a central sap-processing unit.
It has been found that, in cases where a sap-collecting device is not tightly engaged into the tree, the vacuum system also draws outside air into the system.
In applicant's Canadian co-pending application No. 561,977 filed Mar. 21, 1988, there is provided a sap-collecting device with an annular groove in the sap-collecting section thereof to provide a sealing engagement with the outer layer of the tree from which the sap is to be collected.
It has been found that, since the insertion of the section of the device which carries the sealing element, into the layers of the tree is accomplished by hitting that section, the sealing element damages the fibers of the tree.